RICHMOND — Homicide detectives were gathering clues Thursday morning after a man was fatally shot in the central part of the city overnight, police said.

Officers found the man with more than one gunshot wound and unresponsive after responding to the 500 block of 18th Street just before 3:30 a.m. after reports of a shooting. Paramedics and officers tried to save him but were unsuccessful.

Authorities did not immediately identify the victim, but police said they believe the shooting was not a random one. Investigators have not yet determined a motive, but said the man was inside his home when officers found him. They have not identified any suspects.

A shooting outside a Laurel District bar in East Oakland early Saturday left one man dead and four other people wounded, culminating a six-hour period of violence that saw another man killed and three other people wounded in separate incidents, authorities said.